JP2002-331850A describes a driving intention estimator, by which directions that the driver's eyes turn to are projected onto a plane divided into a number of regions, for calculating a distribution of projected eye directions over the divided regions to estimate the driver's driving intention.
Estimating driver's driving intention using eye directions and the frequency distribution thereof are satisfactory to only certain extents. However, the estimation accuracy may vary with different running environments and different drivers because the driver's eye movements associated with the same driving intention may vary with different running environments, and the drivers may show different eye movements associated with the same driving intention.
One approach without relying on the driver's eye movements collects information related to lane markers to estimate a driving intention of the driver. This approach, however, does not address a situation where accurate information regarding the lane marks is lost or unreliable due to variations of the running environment.
Therefore, there is a need remains for a reliable and uninterrupted estimation of driving intention even when a vehicle operates in a constantly changing environment. There is another need to effectively estimate a driving intention even when effective detections or tracking or lane markers cannot be maintained.